Update codecov/codecov-action to v4 (NodeJS 20)

It has been just released, let's update it too.

Author: stronk7

.github/workflows/test.yml

@@ -49,7 +49,7 @@ jobs:
       run: make coverage-phpunit
 
     - name: Upload coverage
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         files: ./build/logs/clover.xml